Language does change with time, and the prevalence and tolerance of swear words in popular culture is much greater than it used to be, but just because this is the kind of language used by their peers is not a good enough reason for Christians to speak the same way.
The Apostle Paul says the following in Eph 5:3–4:
Do not let any kind of sexual immorality and impurity or greed even be spoken of among you, just as is proper for saints, or that which is shameful, or foolish talk, or coarse jokes, which are not fitting, but rather thanksgiving.By writing as he does in v. 3 that sexual immorality, impurity, and greed are not even to “be spoken of among you,” Paul is probably not just forbidding the practice of these particular sins. Instead of taking v. 3 as an oblique way of saying “these sins should not exist among you,” it seems that Paul is saying in v. 3 that it is not fitting for Christians to be talking about ungodly deeds as if they were an appropriate topic of conversation, let alone something that should ever happen within the Christian community. I would argue that Paul seems to have speech acts particularly in mind in vv. 3–4, because the verb ὀνομαζέσθω let it be named is implied in v. 4, where three out of the four nouns listed are clearly speech acts.
Misusing God’s name (whether in abbreviated form or not), or using coarse words referring to the act of sex (whose historical origin lies in taking the act of sex, which in the context of love is a special gift from God, and turning it into a form of abuse), is simply inappropriate for those who are called to be “saints” (i.e., holy ones) in Christ.
According to the Apostle Paul, the process of sanctification involves us putting to death the earthly things (Col 3:5), and this includes getting rid of “blasphemy” and “foul language from your mouths” (Col 3:8).
Apart from the disrespect to God that is shown in mindlessly abusing his name, along with the disrespect that is shown to God as the one who has given us sex as a special gift whenever we use in an unnecessary way coarse words that refer to sex, there is the problem of the use of such language leading to an impaired witness for Christ. Whilesoever there are people in the community who regard this kind of language as crude or rude, the presence of such language of the lips of Christians brings disrepute to the name of Christ. It can also be a source of discouragement to other Christians, and a barrier to fellowship among Christians who find such language unacceptable.
Christ has saved us to be clean and pure, and he desires that our language be clean and pure as well.
